[rrd-developers] Re: rrd_graph and rrd_set_error patches for longer filenames

[Tobias Weingartner]

On Sunday, October 10, Blair Zajac wrote:
> 
> I've been running into some problems with pathnames longer than 255
> characters in rrd_graph.  The following patch fixes these and prevents
> buffer overflows in rrd_set_error, unless the error is longer than
> 4096 characters.

Why stop there?  :-)


> diff -rc ../rrdtool-1.0.7.0/src/rrd_error.c ./src/rrd_error.c
> *** ../rrdtool-1.0.7.0/src/rrd_error.c	Fri Aug 27 12:20:05 1999
> --- ./src/rrd_error.c	Sun Oct 10 18:40:24 1999
> ***************
> *** 16,28 ****
>   void
>   rrd_set_error(char *fmt, ...)
>   {
> !     int maxlen = strlen(fmt)*4;
>       va_list argp;
>       rrd_clear_error();
> -     rrd_error = malloc(sizeof(char)*maxlen);
>       va_start(argp, fmt);
> !     vsprintf(rrd_error, fmt, argp);
>       va_end(argp);
>   }

This ain't perfect, if vsnprintf() exists, I'd use it...


> --- 16,29 ----
>   void
>   rrd_set_error(char *fmt, ...)
>   {
> !     static char buffer[4096];
>       va_list argp;
>       rrd_clear_error();
>       va_start(argp, fmt);
> !     vsprintf(buffer, fmt, argp);
>       va_end(argp);
> +     rrd_error = malloc(sizeof(char)*(strlen(buffer)+1));
> +     strcpy(rrd_error, buffer);
>   }

I fail to see how this will differ much.  Why not just add 4096 to
the above maxlen item?  Same result, buffer at least 4K, but does not
solve the buffer overflow potential...


> diff -rc ../rrdtool-1.0.7.0/src/rrd_graph.c ./src/rrd_graph.c
> *** ../rrdtool-1.0.7.0/src/rrd_graph.c	Fri Oct  1 12:15:28 1999
> --- ./src/rrd_graph.c	Fri Oct  8 23:22:35 1999
> ***************
> *** 180,186 ****
>   
>       /* configuration of graph */
>   
> !     char           graphfile[255]; /* filename for graphic */
>       long           xsize,ysize;    /* graph area size in pixels */
>       col_trip_t     graph_col[__GRC_END__]; /* real colors for the graph */  
>  
>       char           ylegend[200];   /* legend along the yaxis */
> --- 180,186 ----
>   
>       /* configuration of graph */
>   
> !     char           graphfile[1024]; /* filename for graphic */
>       long           xsize,ysize;    /* graph area size in pixels */
>       col_trip_t     graph_col[__GRC_END__]; /* real colors for the graph */  
>  
>       char           ylegend[200];   /* legend along the yaxis */

Why not use MAXPATHLEN if it exists?  And if not, then think of some
POSIXLY decent default value for it?  :-)


--Toby.
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